1. Field of the Invention
The present invention relates to construction technology, and in particular to a method and apparatus for forming earth holes, having fixed walls, in various non-rock soils, and preferably in weak and water-saturated soils.
2. Description of the Prior Art
Known in the art is a tool for forming earth holes, disclosed in the earlier application by V. I. Feklin et al., and comprising a leading casing having a cylindrical sizing portion, and a frontal and rear conical tips provided with spiral tapered surfaces for consolidating soil, and a trailing casing disposed above said leading casing and in coaxial relationship therewith, the trailing casing having a configuration similar to that of the leading one. The leading and trailing casings are connected therebetween by a tubular coupling element provided with a cavity communicating with a duct provided within the trailing casing, and with openings made in the walls.
Such an arrangement allows the fixation of the hole walls to be carried out with various fixing materials in the course of tool intrusion into soil. However, in so doing, the bottom and walls of the hole at the lower portion thereof are left unfixed, which fact in the course of deeping the hole below the level of subsoil waters can result in inundation of the hole and in embarassment of subsequent erection of piles. In the use of such a tool for the fixation of the hole bottom, it is necessary to withdraw the tool to the surface, to supply the fixing material into the hole through the collar thereof, and to accomplish secondary sinking of the whole hole. This results in a substantial increase in the labor consumption of the process and in a decrease in the work quality, since the hole walls at a lower portion thereof drift prior to the fixation process in the course of secondary sinking, the hole becomes filled with water filtering through the unfixed bottom.
In the above-mentioned application there is described a method of making a hole having fixed walls, comprising forming a hole without soil excavation, supplying a fixing material into the hole, and fixing hole walls by pressing the fixing material into the hole walls simultaneously with the hole formation.
Such a method ensures an increase in the stability of the hole walls and a decrease in the labor consumption in the course of the hole formation.
However, in the penetration of the hole bottom down to a level lying below the horizon of subsoil waters, the efficiency of the given method is decreased since in the use thereof is not achieved the fixation of the hole bottom and of the lower portion thereof, thereby resulting in the filtration of water into the hole and in the drift of its walls at the lower portion.
The invention is based on the problem to provide a tool and a method of forming earth holes having fixed walls, which allow the efficiency and reliability of the fixation of walls and a bottom of the hole to be increased.